Many hospitalized patients overestimate their chance of surviving an in-hospital cardiac arrest and do not know what CPR really involves, a University of Iowa study has shown.

The study further showed that this lack of understanding of cardiopulmonary resuscitation may affect a patient's choice about whether to have orders in place to be resuscitated if they are dying.

The study, which also involved researchers in the Iowa City Veterans Affairs Medical Center, appeared in the June 1 issue of the Journal of Medical Ethics.

"The investigation indicates that doctors need to do more to help patients understand CPR procedures and 'do not resuscitate,' or DNR, orders to avoid gaps between treatments used and patients' actual preferences," said the study's lead author Lauris Kaldjian, M.D., Ph.D., associate professor of internal medicine at the UI Roy J. and Lucille A. Carver College of Medicine and a physician with UI Hospitals and Clinics.

"Our study showed that after people were asked about their goals of care and then informed about the chances of survival and good brain function after CPR, nearly one in five said their preferences about CPR had changed," added Kaldjian, who also directs the college's Program in Bioethics and Humanities.

The study involved 135 adults who were interviewed within 48 hours of being admitted to the hospital for general medical treatment from June to August 2007. Many other studies on resuscitation preferences have been based in outpatient settings or on hypothetical scenarios. In contrast, this study interviewed patients while they were being treated in the hospital, Kaldjian noted.

The patients' average age was 48 and just over half were women. Ethnicity was 92 percent white, 4 percent black, 3 percent Hispanic and 1 percent Asian. Very few patients had cancer or heart disease, but 61 percent of them had received intensive care in the past, indicating that they had already experienced serious illness.

The study showed that approximately three out of four patients thought they knew what CPR stood for and what it entails. However, only about 30 percent of patients actually knew that CPR stands for cardiopulmonary resuscitation. More important, only one in four patients (27 percent) understood that CPR in a hospital setting involves the use of an external defibrillator (electricity), and even fewer (7 percent) knew that dying patients would have a tube placed through the mouth and into the windpipe (intubation) and then be placed on a breathing machine. More than half of patients (59 percent) knew that manual chest compressions were used in CPR.

"CPR as it is used in the hospital setting is a more intensive procedure than many patients realized," Kaldjian said.

When patients were asked about the likelihood that CPR would allow them to survive and be discharged from the hospital, the average prediction was 60 percent. The actual chance, on average, is about 18 percent.

When patients were additionally told that the odds of surviving CPR and still having good brain function are even lower -- only about 7 percent -- nearly one in five said that would influence them to change their preference regarding the use of resuscitation.

Kaldjian said that doctors should identify better ways to discuss resuscitation preferences with patients. "Placing these discussions in a wider context of goals of care may make it easier for patients to understand whether CPR is preferable, depending on the likelihood that CPR would help them achieve their care goals," he said.

"The hospital setting is often very busy, and it's hard to take time to talk about resuscitation preferences in a clear, informed and patient-centered way" he said. "We need to find feasible ways of having meaningful discussions, so that patients understand what doctors are telling them, and doctors understand what patients value and prefer."

The investigation involved researchers with the Center for Research in the Implementation of Innovative Strategies in Practice at the Iowa City Veterans Affairs Medical Center.

The study was funded in part by a grant from the UI Carver College of Medicine to two research team members and by funding from the Veterans Administration National Quality Scholars Program to two additional team members.